I never had bad car behavior as an issue myself, but...one of the first things I taught was they stay in the car until I release them!
Car parked dogs door open, they stay until I tell them to come out!
Great way to teach "Stay" at the same time long leash if needed secured to the car. Have them get in say stay if they hop out..back in they go, door open say stay repeat as needed! They get the idea pretty quick! Treat when they get it right!
Translates easily to the house front door!